More than 80 deep sea divers have been deployed to search for crashed AirAsia flight QZ8501 as four more bodies are found, the airline says.

The divers will collect information about two large objects, suspected to be part of the aircraft's fuselage, using a sonar device. They will also search for the lost plane's black box flight recorders.

In a statement, AirAsia said search and rescue officials had found four more bodies on Sunday, taking the number of recovered bodies to 34. So far nine remains have been officially identified, they said.

Rescuers also found debris such as an emergency exit window, luggage, passenger seats and survival kits, which are believed to be from the missing jet.

"Based on past experience, the black box is not far from the plane debris we have found," Mr Soelistyo said.

But he added that none of the searching ships had detected any "pings", the locator signals the black box should transmit after a crash.

Both flight recorders are located near the tail of the plane, but it was unclear whether that part of the aircraft was among the debris found on the seabed.

"Based on the finding of pieces of debris it looks like the body of the aircraft split or cracked and was separated from its tail," said Air Force Lt Col Johnson Supriyadi, a search and rescue official co-ordinating the operation from the southern Borneo town of Pangkalan Bun.

The suspected wreckage is lying in water around 30 metres deep, which experts said should make it relatively straightforward to recover.

Nine ships from four countries have converged on the area, with teams of divers including seven Russian experts standing ready. However, strong winds and four-metre high waves have kept progress agonisingly slow.

The airline has come under pressure from Indonesian authorities, who have suspended its Surabaya to Singapore operations saying the carrier only had a licence to fly the route on Mondays, Tuesdays, Thursdays and Saturdays.

Indonesia AirAsia said it would co-operate with the transport ministry while it investigates the licence.

A joint statement from Singapore's civil aviation authority (CAAS) and Changi Airport Group said that AirAsia had the necessary approvals to operate a daily flight between Surabaya and Singapore.